1993 Ford Taurus Dim headlights

I recently acquired an old Tarus to use as a local commuter. It's in excellent condition in spite of age and mileage - except for headlights, tail lights and dash lights, all of which are dim. Battery seems to be good. Dome lights are very bright even if the car is not running, and it cranks and starts great even in very cold weather.
thanks!
sam

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Thursday, January 1st, 2009 AT 2:18 AM

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JGAROFALO

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Sounds like a grounding problem initially, but since you are referring to 3 different light groups, I would be more inclined to point to something common to all 3 light groups. What comes to mind is the headlight switch. It is possible that there is a high resistance in the switch or the connector that is causing the lights to be dim.

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Thursday, January 1st, 2009 AT 4:05 AM

SAMYODER

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Followup question please:

Assume for the moment that your idea about a bad ground is correct, (that was actually my initial assumption as well), where would I look for a ground that effects both headlights equally?
Thanks
sam

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Friday, January 2nd, 2009 AT 11:48 AM

DAVE H

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Just a little interuption until jgarofalo gets back to you

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Friday, January 2nd, 2009 AT 1:11 PM

JGAROFALO

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Initially, it sounds like a grounding problem, but after some thought, I am more inclined to point at the headlight switch or connector.

There are several grounds. There are ground points at the radiator support, near the wiring harnesses a bit before the headlights. There is at least one ground at the rear of the car behind one of the taillight assemblies. There are also several ground points inside the car. ONE bad ground would more likely affect one or two lights - not ALL of them. The one part that is common to all of the lights is the headlight switch. High resistance inside the switch or high resistance at the connector would be more likely to make ALL of the lights dim.

The first test I would make would be to remove the switch from the instrument panel, leaving it connected to the harness. With the lights OFF, check the voltage at the BLACK wire with ORANGE stripe. This should read the same as the battery voltage. Then, turn ON the lights, and recheck the same voltage. If it is still at battery voltage, then check voltage at the other wires with the lights ON.

If you find the voltage drops at the BLACK/ORANGE wire with the lights on, then you have a high resistance connection in the circuit from the battery to the switch. If the voltage does NOT drop, then it is most likely a bad switch.

Once again, I think that ONE ground will normally NOT dim ALL of the lights.